Multi-Wavelength Currency Bill Sensor Arrangement
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Solution Overview
Problem
Currency processing devices face challenges in efficiently processing a high number of mixed denomination and series of currency bills due to the increasing size of the master data set, which complicates the determination of bill orientation and authenticity, leading to higher costs and reduced efficiency.
Innovation Solution
A currency processing device equipped with a currency bill sensor arrangement that utilizes multi-wavelength optical sensing to determine the face orientation and authenticity of banknotes by analyzing reflectance differences, allowing for reduced master data sets and improved processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional single-wavelength optical sensing is used to process currency bills, then the device can handle basic denomination identification, but the processing speed is limited and the master data set size increases with more denominations and series
Solution Approach 1:
The patent applies parameter changes by using multi-wavelength optical sensing instead of single-wavelength sensing. The sensor arrangement measures reflectance at multiple wavelengths (e.g., blue, green, red, infrared) to generate a spectral signature for each bill. This additional spectral parameter information allows for more accurate bill identification and orientation determination, enabling faster processing speeds (up to 1000 bills per minute) while reducing the master data set size needed for comparison, as the spectral signatures provide more distinctive characteristics for differentiation.
2Productivity
If multi-wavelength optical sensing is implemented to determine face orientation and reduce master data set size, then processing efficiency improves, but the device complexity and initial cost increase
Solution Approach 1:
The patent implements universality by designing a multi-wavelength sensor arrangement that performs multiple functions simultaneously. The same sensor system measures both the spectral signature for denomination identification and the reflectance differences for face orientation determination. This multi-functional approach increases processing efficiency without requiring separate sensing systems for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent uses parameter changes by measuring reflectance at multiple wavelengths to extract multiple parameters from a single sensing operation. The system measures absolute reflectance values and reflectance differences (ΔR) between wavelengths, providing rich information for both denomination identification and face orientation determination. This efficient parameter extraction method improves processing efficiency while keeping the sensor arrangement complexity manageable through integrated measurement.
3Productivity
If high-speed transport mechanism is used to process 1000+ bills per minute, then productivity increases, but the sensing system must operate at higher speeds requiring reduced processing power
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing spectral signatures and reflectance difference patterns for various bill types during system initialization. When a bill is sensed at high speed, the system compares the measured parameters against these pre-established reference patterns rather than performing complex analysis in real-time. This preliminary preparation enables high-speed processing (1000+ bills per minute) with reduced processing power requirements during actual operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables rapid processing of mixed denomination banknotes at high speeds, reducing processing power requirements and costs by accurately determining face orientation and authenticity using reflectance differences, thereby enhancing the efficiency and cost-effectiveness of currency processing.
Implementation Method 1
a cylindrical lens positioned to receive the first and second wavelengths of light from the multi-wavelength light source, the cylindrical lens illuminating an elongated strip of light on a surface of one of the plurality of currency bills, the cylindrical lens being configured to receive light reflected from the surface of the one of the plurality of currency bills
Implementation Method 2
a photodetector positioned to receive the reflected light, the photodetector generating an electrical signal in response to the received reflected light
Data Source
AI summary
A currency processing device for receiving a stack of U.S. currency bills and rapidly processing all the bills in the stack, the device comprising: an input receptacle adapted to receive a stack of U.S. currency bills of a plurality of denominations, the currency bills having a wide dimension and a narrow dimension; a transport mechanism positioned to transport the bills, one at a time, in a transport direction from the input receptacle along a transport path at a rate of at least about 1000 bills per minute with the narrow dimension of the bills parallel to the transport direction; a currency bill sensor arrangement positioned along the transport path, the currency bill sensor comprising: i) a multi-wavelength light source configured to emit a first wavelength of light and a second wavelength of light; ii) a cylindrical lens positioned to receive the first and second wavelengths of light from the multi-wavelength light source, the cylindrical lens illuminating an elongated strip of light on a surface of one of the plurality of currency bills, the cylindrical lens being configured to receive light reflected from the surface of the one of the plurality of currency bills; iii) a photodetector positioned to receive the reflected light, the photodetector generating an electrical signal in response to the received reflected light; iv) a processor configured to receive the electrical signal generated by the photodetector; wherein, the processor is configured to determine whether the surface of the one of the plurality of currency bills is a primary surface or a secondary surface based on the electrical signal.